Method of tunneling and tunneling shield with a drag loader

ABSTRACT

AT ITS FORWARD END THE BOOM SUPPORTS BOTH A POWER TOOL, ADAPTED FOR DIGGING AT THE TUNNEL FACE, AND TO A HOE. THE REAR END OF THE BOOM IS PIVOTALLY CONNECTED TO A CARRIAGE WHICH IS SUPPORTED INSIDE THE SHIELD FOR FORE AND AFT MOVEMENT OVER BOTH THE FORWARD PORTION OF A CONVEYOR AND A RAMP WHICH DISCHARGES ONTO THE CONVEYOR. THE TOOL IS USED FIRST TO DIG THE TUNNEL FACE, AND THEN IS RETRACTED AND THE HOE IS USED TO DRAW MINED MATERIAL UP THE RAMP AND ONTO THE CONVEYOR.

Jan. 19, 1971 4 3,556,598

' METHOD OF TUNNELING AND TUNNELING SHIELD WITH A DRAG LOADER Filed Dec 10, 1968 4 Sheets-Sheet 1 Q QE NN; 8 2 WW4 III ATTORNEYS Jan. 39, 1971 FIKSE 3,555,53Q

METHOD OF TUNNELING AND TUNNELING SHIELD WITH A DRAG LOADER Filed Dec. 10, 1968 4 Sheets-Sheet 2 INVENTOR. TYMAN H. FIKSE ATTORNEYS T. H. FIKSE 5m. w, m1

METHOD OF TUNNELING AND TUNNELING SHIELD WITH A DRAG LOADER 4 Sheets-Sheet 4,

Filed Dec. 10, 1968 U WM G I F INVENTOR. TYMAN H. FIKSE ATTORNEYS United States Patent 3,556,599 METHOD OF TUNNELING AND TUNNELING SHIELD WITH A DRAG LOADER Tyman H. Fikse, Renton, Wash. (1459 Loraine St., Enumclaw, Wash. 98022) Filed Dec. 10, I968, Ser. No. 782,567 Int. Cl. EOlg 3/03 US. Cl. 299-11 18 Claims ABSTRACT OF THE DISCLOSURE At its forward end the boom. supports both a power tool, adapted for digging at the tunnel face, and to a hoe. The rear end of the boom is pivotally connected to a carriage which is supported inside the shield for fore and aft movement over both the forward portion of a conveyor and a ramp which discharges onto the conveyor. The tool is used first to dig the tunnel face, and then is retracted and the hoe is used to draw mined material up the ramp and onto the conveyor.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to power excavating equipment and its arrangement within a tunneling shield, and to a tunneling technique.

Description of the prior art It is know to equip a tunneling shield with a forward ramp leading upwardly and rearwardly to a discharge position over the forward end position of an endless belt conveyor, and to utilize the forward motion of the shield to move loose material up the ramp. This basic arrangement is disclosed by Canadian Pat. No. 340,463, granted Mar. 27, 1934, to Warner et al.

It is also known to equip such a ramp with a rotating screw type conveyor for moving the material up the ramp. An arrangement of this type is disclosed by US. Pat. No. 3,355,215, issued Nov. 28, 1967, in connection with a machine which also includes an oscillating cutter-- head for mining the tunneling face.

US. Pat. No. 2,836,408, issued May 27, 1958, to A. L. Barrett, discloses combining a screw conveyor with a rotary cutterhead in a non-shield type mining machine, and using such screw conveyor for moving the mined material up a ramp and onto a power conveyor.

A different type of power excavator for a tunneling shield is disclosed by French Pat. No. 1,388,527, published Feb. 5, 1965. It includes a frame supporting a forwardly extending boom which carries a cutting tool at its forward end. The boom is operable for moving the cutting tool in all directions across the tunnel face. The frame is track mounted for fore and aft movement axially of the tunnel. In use the tool is used to pick up material from the tunnel face. The frame is then moved rearwardly along the track to place the tool over a take-out conveyor, and the boom and tool are rotated to deposit the material onto the conveyor.

SUMMARY OF THE INVENTION According to the present invention a tunneling machine is provided with a rectractable boom carrying a combined digging and hoeing tool at its forward end. The tool is first moved forwardly and used to dig or mine the tunnel face, with the mined material being allowed to drop. Periodically the digging is stopped, the shield is shoved forwardly, and the tool is retracted and used in hoe fashion to draw the mined material up a ramp and onto a conveyor. A principal advantage of this arrangement is that Patented Jan. 19, 1971 the digging and rearward movement of the material may be performed by selective operation of a single power operated mechanism.

Other aspects of the invention are hereinafter described in connection with the illustrated embodiment.

BRIEF DESCRIPTION OF THE DRAWING In the drawing like element designations refer to like parts, and:

FIG. 1 is a view partially in vertical axial section and partially in side elevation of a tunneling machine typifying the present invention, such view showing the machine in an inuse position within a tunnel, and showing an air hammer portion of the excavating tool being used for digging the tunnel face;

FIG. 2 is a shortened view similar to FIG. 1, showing the shield in the process of being jacked forwardly, and the hoe portion of the excavator tool being used for drawing material rearwardly and up the ramp onto the conveyor;

FIG. 3 is a front elevational view of the tunneling machine showing the breasting doors relatively tight together in extended or breasting positions, with the internal elements of the tunneling machine omitted for the sake of clarity of illustration;

FIG. 4 is a view similar to FIG. 3, but showing the breasting doors in their retracted positions, and showing the elevating ramp for the mined material and the frame portions only of the excavating equipment in front elevation;

FIG. 5 is a view partially in horizontal axial section and partially in top plan of the tunneling machine, with portions of some elements cut away for clarity of illustra-- tion of internal parts;

FIG. 6 is a fragmentary side elevational view of one of two attitude control wings which are embedded in the lower outer side portions of the shield;

FIG. 7 is a sectional view taken substantially along line 77 of FIG. 6, and presenting a top plan view of the attitude control wing;

FIG. 8 is a fragmentary vertical section view taken through the upper forward portion of the shield and presenting a side elevational view of one of the upper breasting doors in its retracted position;

FIG. 9 is an enlarged scale view of the rearward mounting portion of the tool boom, such view being partially in top plan and partially in horizontal axial section;

FIG. 10 is a fragmentary pictorial view of the forward end portion of the boom and the preferred form of dual purpose tool carried thereby; and

FIG. 11 is a view similar to FIG. 10, but showing a second form of dual purpose tool.

DESCRIPTION OF THE PREFERRED EMBODIMENT The tunneling shield 10 includes a forward section 12 which may be beveled back from top to bottom as illustrated; an intermediate section 14; and a tail section 16. The shield 10 is moved forwardly by a plurality of thrust rams 18 having cylinder portions carried by the intermediate section 14 and rearwardly extendible pistons which react against a husky ring beam 20.

As is conventional in the tunneling field, the tunnel lining is continuously added onto and extended forwardly as the shield is advanced forwardly. The illustrated form of tunnel lining is composed of axially spaced girth ribs or beams 22 and wooden plank lagging 24 bridging the Spaces between the beams 22. The ring beam 20 abuts against the forward rib 22. After the shield has been shoved forwardly an amount approximately equal to the full throw of the thrust rams 18, the thrust rams 18 are retracted, the ring beam is moved forwardly, and a new section of lagging and a new forwardmost girth rib 22 are installed under cover of the tail section 16. As should be apparent, the shield 10 serves to support the earth formation in the region where excavation is taking place and the tunnel lining supports the tunnel in its extent rearwardly of the shield 10.

According to the invention a boom including power excavator E is provided for both (1) digging or mining the tunnel face 26 and (2) drawing the mined material rearwardly and up a ramp 28 to be discharged therefrom onto an endless belt type conveyor 30, or the like, which moves such material rearwardly and deposits it into mining cars 32 or some other form of material carry-out means.

The excavating equipment E includes a main suppOrt frame F which is in the nature of a structural triangle. It includes an upper carriage support portion 34 which is secured at its forward end to two side placed support ears 36, 38 which depend from an intermediate portion of the shield section 14. Carriage support portion 34 is disposed generally horizontally and extends from its connection points to the ears 36, 38 axially rearwardly through the tail section region 16 and possibly also into the region of the tunnel rearwardly of the tail section 16. The rear end of the carriage support portion 38 is supported only by a pair of side located struts 40, 42. The rear ends of the struts 40, 42 are pin connected to the carriage support portion 34 and the forward ends of struts 40, 42 are pin connected to lower portions of the shields intermediate section 14. Thus, the support frame F is structurally connected only to the relatively husky intermediate section 14 of the shield 10 and extends through free space both vertically between and rearwardly of the securement points 36, 38, 44, 46.

Referring to FIG. 5 in particular, the carriage support portion 34 is shown to comprise a pair of laterally spaced, parallel, tubular rails 48, 50. It is the front end portions 52, 54 of the rails 48, which are connected to the mounting cars 36, 38. The rear ends of the rails 48, 50 are interconnected by a cross frame 56 which includes a box-like central extension 58 having its own rear end cross member 60. A carriage is mounted on the rails 48, 50 by a pair of mounting sleeves 62, 64, respectively. The carriage frame comprises a pair of vertical side plates 66, 68 interconnected by a lateral beam 70. The side plates 66, 68 are connected to the mounting sleeves 62, 64, such as by tie members 72.

A two-piston thrust ram assembly 74 is interconnected between the cross beam 70 and the end member 60. Such assembly 74 comprises an elongated cylinder 76 supported between its ends by a cross member 78 carrying guide sleeves 80, 82 at its opposite ends which surroundingly engage the tubular rails 48, 50. A first piston 84 is housed within the forward portion of cylinder 76 and a second I piston 86 is housed in the rearward portion of cylinder 76. The forward end portion 88 of the piston rod for piston 84 is connected to the cross beam 70 and the rearward end 90 of the piston rod for piston 86 is connected to the cross member 60. Fluid supply and vent lines 92, 94 are provided through the cylinder wall on the rod sides of the piston heads 96, 98 and a supply and return line 100 is provided for delivering fluid into the space between the piston heads 96, 98. In FIG. 5 the carriage is shown in a rearmost or retracted position. The carriage is moved forwardly or extended by directing fluid through line 100 into space 102 While at the same time removing fluid via lines 92, 94.

Referring now to FIGS. 1, 2, 5 and 9, in particular, the excavating equipment is shown to comprise a boom means supported from the forward portion of the carriage. More specifically, the boom means is shown to comprise a rotatable tool shaft 104 carrying a mining or excavating tool T at its forward end. A mounting sleeve 106 surrounds the rearward portion of shaft 104 and at its rear end is connected to a yoke 108 which is pivotally connccted to a cross beam 110 for sideways pivotal movement about an axis 112. The beam 110 is itself mounted for pivotal movement about a generally horizontal axis 114 (FIG. 1).

The pivotal connections providing swinging movement of the boom means about axes 112 and 114 serve to mount the boom means, and hence the tool T carried thereby, for universal movement within the confines of the shields forward section 12. In the illustrated embodiment three independently controllable hydraulic rams are provided for swinging the boom means. The first ram 116 is pivotally connected at one of its ends to an upper forward portion of the carriage, for pivotal movement about a horizontal axis 118. At the opposite end it is connected to a forward portion of the mounting sleeve 106 for pivotal movement about a generally horizontal axis 120. Second and third rams 122, 124 are provided on opposite sides of the boom means. Ram 122 is pivotally connected at one end to a forward right side extension of the rotatablebeam 110, for sideways pivotal movement about an axis 126. The opposite end of ram 122 is pivotally connected to the mounting sleeve 106 for sideways pivotal movement about an axis 128. The rear end of ram 124 is pivotally connected to an opposite end extension of beam 110, for sideways pivotal movement about an axis 130. The forward end of ram 124 is pivotally connected to the sleeve 106 for sideways pivotal movement about an axis 132. Rams 122, 124 are situated in a common plane with the boom shaft 104, and axes 126, 128, 130, 132 are substantially perpendicularly related to such plane. As should be evident, retraction of the piston in one of side rams 122, 124 accompanied by extension of the piston in the other side ram causes a sideways movement of the boom means and the excavator tool T. Extension and retraction of the piston in ram 116 causes vertical movement of the boom means and the tool T.

In preferred form, an operators station 134 is suspended from the carriage between the side plates 66, 68. The operator sits on a seat 136 and has the controls for the rams 116, 122, 124 in front of him.

As earlier mentioned, the tool shaft 104 is rotatable. As shown by FIG. 9, it is rotated by a hydraulic motor 136, or the like coupled to the rear end of shaft 104 and supported within the open center of the yoke 108. The motor 136 may be used to merely rotate or revolve the shaft 104, and the tool T, a portion of one revolution, or to continuously rotate the shaft 104 and the tool T. This latter arrangement will be hereinafter described in greater detail.

To some extent the hydraulic motor 136 can be used to hold or position the shaft 104 and the tool T. However, since some rotary hydraulic motors have a tendency to creep, a position lock mechanism 138 may be provided for holding the shaft 104 in one or more set positions. In FIG. 9 the lock mechanism 138 is shown to consist of a lever 140 pivotally supported near its middle at 142. A compression spring 144 is situated between the forward end of the lever 140 and the support sleeve 106. The opposite end of the lever 140 carries a lock pin 146. The lock pin 146 is shown to be pivotally connected to the lever 140 by a pin means 148 which extends from pin 146 through a longitudinal slot in lever 140. The inner end of pin 146 is shown to project through first an opening in support sleeve 106 and then into an opening or socket 150 in the shaft 104. When it is desired to lock the shaft 104 in position relative to sleeve 106, the pin 146 is set in place. Plural openings 150 circumferentially spaced about the shaft 104 may be provided so that there is a choice of set positions for the shaft 104 and the tool T. As should be evident, the shaft 104 and the mounting sleeve 106 may be easily decoupled by the user merely depressing the spring end of lever 140 until the pin 146 is free of both openings. Once it is out of the opening in sleeve 106 it can be swung to one side until it is again desired to use the lock mechanism 138.

As shown by FIG. 9, the drive shaft 152 of motor 136 is keyed to a circular rear end member 154 which is bolted to a reduced diameter plug member 156 constituting a rearward portion of the shaft 104. A radial thrust bearing 158 is interposed between the rear surface of member 154 and the support wall 160, and a combination bearing 162 is interposed radially between plug 156 and the wall of sleeve 106 and axially between the forward surface of butt plate 154 and rear end surfaces of the tubular portion of shaft 104 and sleeve 106.

In preferred form, the excavating tool T comprises a pneumatic hammer 164 having a point 166 directed generally perpendicularly of the boom shaft 104, and an oppositely directed paddle or hoe portion 168. An air supply line 170 is provided for leading air into the hammer 166.

As best shown by FIGS. 1 and 2, a thrust ram 172 is interconnected between a mounting ear 174 projecting laterally from the shaft 104 adjacent where it immerges from sleeve 106, and a mounting ear 176 offset towards the hoe portion of. the tool T from the point of connection of the tool T to the shaft 104. Tool T is pivotally connected to the forward end of shaft 104 for pivotal movement about a transverse axis 178. The two ends of thrust rams 172 are pivotally attached to their support ears 174, 176, respectively, for movement about axes which are parallel to axis 178. Thrust ram 172 is independently controlled by the operator. The operator control panel includes a set of controls for this thrust ram in easy reach of the operator. Thrust rams 116, 122, 124 and 172 individually and collectively constitute attitude control means for the boom means and the tool T carried thereby.

In operation, the boom means is suitably moved by the operator to place the point 166 of the digging tool at the spot where it is desired to cut or mine the face material. During operation of the pneumatic hammer the thrust rams 116, 122, 124, 172 are selectively operated to suitably brace the boom means and resist the reaction forces imposed on it by the reciprocating point 166 as it works on the tunnel face 26.

The shield may be shoved forward by the rams 18 during the mining process, or the shield 10 may be intermittently thrust forwardly during the periods the tool T is used for drawing the mined material rearwardly up the ramp 28 and onto the traveling belt 180 of the conveyor 30. The operator readies the tool T for this latter function by rotating the shaft 104 from the position it is in for digging into the position shown by FIG. 2. The thrust ram 74 is then operated to move the carriage rearwardly, carrying with it the boom means and the tool T. As the tool T moves rearwardly the hoe portion 168 collects mined material in front of it and moves it rearwardly up the ramp 28. As shown by FIG. 10 the hoe portion 168 may be provided with a pair of rearwardly turned side fins 182 dihedrally related to the general plane of the hoe portion 168 for the purpose of minimizing spillage around the sides of the hoe portion 168.

As shown by FIG. 1, the rear portion 184 of the conveyor is elevated, and is supported in the elevated position by a traveling support 186, preferably in the form of one or more pairs of laterally spaced support members having wheels 188 at their lower ends which ride on the floor 190, or on tracks therefor. During construction of a tunnel it is common to build a slightly elevated floor 190 in the tunnel so as to provide a flat base surface of substantial width. Muck car tracks 192 are secured to the floor 190. These tracks are sectional and are continuously extended forwardly in the tunnel as the shield is moved forwardly and the tunnel itself is extended.

According to the invention, the forward end of the conveyor 30 is secured to the shield 10, such as by a cross chain 192 which is secured intermediate its ends to the conveyor frame and at its ends to lower opposite side portions of the ramp 28. The rear portion of the conveyor 30 is supported only by its mobile support 186. Hence,

6 the conveyor 30 is coupled in trailer fashion to the shield and is pulled forwardly by the shield as the shield advances.

The chain type support has the effect of substantially isolating the conveyor 30 from roll movement the shield may experience as it is thrust forwardly. As shown by FIGS. 4, 6 and 7, retractable attitude control wings 194 are provided on the side of the shield 10 and may be operated to at least partially compensate for shield roll. As shown by FIG. 7, the wings are pivotally mounted at their forward ends, such as by a single pin 196. A hydraulic ram 198 is interconnected between two pivot pins 200, 202, one carried by a fixed mount 204 secured to the shield wall and the other carried by the wing 194. An arcuate roll of openings 206 may be provided in the rear portion of the wing 92 so as to be movable over an opening provided in a fixed member 208 secured to the shield wall, so that the wing 194 can be locked into position by dropping a lock pin 210 through one of the openings 206 and the opening in member 208. As shown by FIG. 6, the wings are not horizontal, but rather sloped downwardly from front to rear. This gives them a slight angle of attack so that as the shield is moved forwardly with both wings extended a lifting force will be opposed on the wings causing the shield to veer upwardly somewhat. At other times one wing 194 is retracted and the other alone is used so as to impose an upwardly directed force at only one side of the shield for correcting roll.

Referring to FIGS. 1, 2 and 5, according to the invention the intermediate sections 16 of the shield includes a pair of stabilizing and guide rails 210, 212, one on each side of the shield. These members 210, 212 are substantially parallel and are spaced laterally apart from each other and about midway between the top and bottom of the shield. Grooved follower wheels 214, 216 are carried by the thrust ring 20 and follow along the upper edges of the guide tracks 210, 212. The guide tracks 210, 212 and the follower wheels 214, 216 serve to stabilize and facilitate movement of the ring 20.

A plurality of breasting doors D are mounted on the forward section 12 of the shield 10. Each door is generally pie shaped but has a blunt rather than a sharp small end. The curvature of the arcuate ends of the doors is made to at least closely match the curvature of the shield wall 12, and the arcuate outer ends of the doors D are pivotally connected to the inner surface of wall 12. The arrangement shown by FIG. 3 includes four doors which together substantially close the upper half of the forward opening in the shield. Preferably the doors D are sized so that when they are extended (FIG. 3) the side edges of adjacent doors substantially contact each other and there is at least somesemblance of mutual bracing at such edges and structural continuation of the doors D. Preferably, rather than being planar the doors are convexly curved on their forward sides and concavely curved on their rearward sides, so that there is some degree of keying together of the doors when they are all extended. Each door is provided with its own independently controllable thrust ram R. One end of each ram R is pivotally connected to its door D at a pivot point P1 that is longitudinally spaced along the door D from the hinge H which connects the door to the shield wall 12. The opposite end of the ram R is pivotally connected to the Wall 12 at a more rearward position P2. The pivotal axes are substantially perpendicularly related to a radial plane, and the ram R is positioned so that it moves within said radial plane as the door D is extended and retracted.

When soft ground is encountered and the tunnel face does not stand up but rather tends to flow into the shield the doors D are extended so as to substantially close off the upper portion of the entrance into the shield 10. When the doors are in their breasting position the soft material will slope from the lower edges of the two lower doors downwardly and inwardly to a point of intersection with the ramp 28, with the angle of repose varying in accordance with the composition and flow characteristics of the material. An important feature of the doors is that they can be quickly moved into a breasting position. This is quite often necessary because a breakdown of the tunnel face with an inward rush of the material quite often happens without any warning to the personnel working inside the shield. Although the rams R are independently operable, the control system therefor should be adapted for also moving all doors at once, so that they can all be quickly moved together into a breasting position in the event a sudden and unexpected flow occurs.

The excavating tool T shown by FIG. 11 is designed to be continuously rotated and to cut into the tunnel face as it is rotated. To facilitate cutting it is shown to comprise a plurality of cutters C. It is also shaped so that it can be used in hoe fashion to draw the mined material up the ramp and onto the conveyor 30.

The purpose of the illustrated embodiment is to provide an understanding of the invention. The following claims set forth the legal limits of the invention.

What is claimed is:

1. A tunneling machine comprising:

a tunneling shield including means providing overhead protective cover at the face region of the tunnel, and support frame means therefor adapted to be advanced as mining progresses;

an endless conveyor for moving mined material rearwardly to a pickup station, said conveyor having a forward end portion within the protective confines of said shield, and supported on a lower portion of said frame;

a ramp within the protective confines of said shield, said ramp having a lower forward end, said ramp rising rearwardly and having an after portion overhanging the forward end portion of said conveyor;

boom means having front and rear ends;

elevated support means within the protective confines of said shield at a level above the levels of said ramp and at least the forward portion of said conveyor;

carriage means mounted on said support means for both forward and rearward movement generally axially of the tunnel;

means pivotally connecting the rear end of said boom means to said carriage means;

an excavator tool mounted at the forward end of said boom means, said tool having a broad hoe portion;

means for advancing and retracting said carriage along said support means, and in turn said boom means and said tool carried thereby, relative to the tunneling shield and longitudinally of the tunnel; and attitude control means for placing said hoe portion in a position for drawing mined material rearwardly and upwardly over said ramp as said carriage, boom means and tool are being retracted. 2. The tunneling machine of claim 1, wherein said shield includes means for advancing it axially forwardly, and said conveyor has an elevated rear end portion and includes a mobile support for said rear end portion, with 60 said conveyor being secured at its front end to said shield and in use being towed by said shield in trailer fashion.

3. The tunneling machine of claim 1, wherein said boom means comprises a rotatable tool shaft and means for supporting same, and said excavator tool is mounted on the tool shaft, so as to be rotatable therewith, and wherein said excavator tool further includes a second excavating portion differing in character from said hoe portion and situated circumferentially about the tool shaft from said hoe portion.

4. The tunneling machine of claim 3, wherein said second excavating portion is a reciprocating point type hammer, and extensible brace means extends between said carriage and said boom means for bracing said boom means during use of said hammer,

5. The tunneling machine of claim 1, wherein said boom means comprises a rotatable tool shaft and support means which at least partially surrounds the rear portion of said shaft and rotatably supports said shaft, wherein the means pivotally connecting the rear end of said boom means to said carriage means is interconnected between said carriage means and said tool shaft support means, and wherein said attitude control means comprises at least one hydraulic ram pivotally connected at one of its ends to an upper forward portion of said carriage and pivotally connected at its other end to said tool shaft support means, and at least one additional hydraulic ram pivotally connected at one of its ends to a side portion of said carriage and pivotally connected at its other end to 15 said tool shaft support means.

said elevated support means comprises a pair of parallel,

elongated rods, and said carriage means includes a support sleeve surroundingly engaging each said rod and frame means interconnected between said sleeves.

8. The tunneling machine of claim 1, wherein the means for advancing and retracting said carriage comprises a compound thrust ram assembly comprising an elongated cylinder extending in the direction of carriage movement, first and second piston rods inside said chamber, each having a piston head at its inner end, means connecting the forward end of the forward piston rod to one of said shield frame and said carriage means, means connecting the rearward end of the rear piston rod to the other of said shield frame and said carriage means, and means for supplying fluid into, and draining fluid out 5 from, the space between the two piston heads.

9. The tunneling machine of claim 1, further comprising means pivotally mounting the excavator tool at the forward end of said boom means, and wherein said attitude control means includes a hydraulic thrust ram pivotally connected at one end to the excavator tool and at its other end to the boom means, for both swinging the excavator tool in position relative to the boom means and bracing the excavator tool in a set position relative to the boom means.

10. The tunneling machine of claim 9, wherein the excavator tool is elongated and the said broad hoe portion is at one end thereof, wherein a percussion hammer is at the opposite end of said tool, wherein the means pivotally connecting the excavator tool onto the boom means is located intermediate the ends of the excavator tool, and wherein the thrust ram controlling the attitude of the tool is connected at its forward end to the excavator tool on the hoe portion side of the pivot means.

11. The tunneling machine of claim 9, wherein said boom means comprises a rotatable tool shaft and support means therefor which at least partially surrounds the rear portion of said shaft, wherein the means pivotally connecting the rear end of said boom means to said carriage means is interconnected between said carriage means and said tool shaft support means, and wherein said attitude control means also comprises at least one hydraulic ram pivotally connected at one of its ends to an upper forward portion of said carriage and pivotally connected at its other end to said tool shaft support means.

12. The tunneling machine of claim 11, wherein said attitude control means comprises at least one additional hydraulic ram pivotally connected at one of its ends to a side portion of said carriage and pivotally connected at its other end to said tool shaft support means.

13. The tunneling machine of claim 1, wherein said boom means comprises a rotatable tool shaft and a support means for said shaft located to the rear of said boom means, and wherein the means pivotally connecting the rear end of said boom means to said carriage means comprises a support member mounted on said carriage means 9 for angular movement about an axis extending transversely of the tunnel, and means connecting the boom shaft support means to said transverse member for pivotal movement about an axis which is substantially perpendicular to the said transverse axis.

14. The tunneling machine of claim 13, wherein the said attitude control means comprises a pair of side placed thrust rams, each of which is pivotally connected at its forward end to a portion of saidboom shaft support means and at its rearward end to the end portion of the transverse member on its side of the boom means.

15. The tunneling machine of clai 13, wherein said attitude control means comprises at least one thrust ram pivotally connected at its forward end to the said tool shaft support means and at its rearward end to an upper portion of the carriage means.

16. The tunneling machine of claim 13, wherein said boom means further comprises a motor mounted in the rear end region of the boom means forwardly of the two pivot axes, and drive transmission means interconnected.

between said motor means and the rear end of the boom shaft.

17. A tunneling method comprising: digging a tunnel face by use of a digging tool supported at the end of an elongated boom which is itself supported within a tunneling shield; swinging the boom sideways and/or up and down as necessary to place the digging tool in contact with a location on the tunnel face where digging is desired;

following accumulation of some mined material at the 3 lower front portion of the shield, retracting the entire boom so as to move the tool axially rearwardly through said shield, and while retracting said boom using a portion of the tool in hoe fashion to draw the accumulated material rearwardly up a material ramp supported in the shield, and onto a removal conveyor extending rearwardly through the tunnel from 5 a receiving position below the after end of said ramp;

and progressively jacking the tunneling shield forwardly accompanied by a continuous extension of a lining 10 for the tunnel rearwardly of the shield.

18. A tunneling method according to claim 17, further comprising using a percussion hammer type digging tool and bracing said boom from its side generally towards the direction of hammer movement into the face material,

15 so that the brace means carries some of the hammer generated forces.

References Cited UNITED STATES PATENTS ERNEST R. PURSER, Primary Examiner 0 US. Cl. X.R. 

